Med Diet 4.0: the Mediterranean diet with four sustainable benefits.

OBJECTIVE: To characterize the multiple dimensions and benefits of the Mediterranean diet as a sustainable diet, in order to revitalize this intangible food heritage at the country level; and to develop a multidimensional framework - the Med Diet 4.0 - in which four sustainability benefits of the Mediterranean diet are presented in parallel: major health and nutrition benefits, low environmental impacts and richness in biodiversity, high sociocultural food values, and positive local economic returns. DESIGN: A narrative review was applied at the country level to highlight the multiple sustainable benefits of the Mediterranean diet into a single multidimensional framework: the Med Diet 4.0. Setting/subjects We included studies published in English in peer-reviewed journals that contained data on the characterization of sustainable diets and of the Mediterranean diet. The methodological framework approach was finalized through a series of meetings, workshops and conferences where the framework was presented, discussed and ultimately refined. RESULTS: The Med Diet 4.0 provides a conceptual multidimensional framework to characterize the Mediterranean diet as a sustainable diet model, by applying principles of sustainability to the Mediterranean diet. CONCLUSIONS: By providing a broader understanding of the many sustainable benefits of the Mediterranean diet, the Med Diet 4.0 can contribute to the revitalization of the Mediterranean diet by improving its current perception not only as a healthy diet but also a sustainable lifestyle model, with country-specific and culturally appropriate variations. It also takes into account the identity and diversity of food cultures and systems, expressed within the notion of the Mediterranean diet, across the Mediterranean region and in other parts of the world. Further multidisciplinary studies are needed for the assessment of the sustainability of the Mediterranean diet to include these new dimensions.

Socioeconomic inequalities in childhood overweight: heterogeneity across five countries in the WHO European Childhood Obesity Surveillance Initiative (COSI-2008).

BACKGROUND: Excess risk of childhood overweight and obesity occurring in socioeconomically disadvantaged families has been demonstrated in numerous studies from high-income regions, including Europe. It is well known that socioeconomic characteristics such as parental education, income and occupation are etiologically relevant to childhood obesity. However, in the pan-European setting, there is reason to believe that inequalities in childhood weight status may vary among countries as a function of differing degrees of socioeconomic development and equity. SUBJECTS AND METHODS: In this cross-sectional study, we have examined socioeconomic differences in childhood obesity in different parts of the European region using nationally representative data from Bulgaria, the Czech Republic, Lithuania, Portugal and Sweden that were collected in 2008 during the first round of the World Health Organization (WHO) European Childhood Obesity Surveillance Initiative. RESULTS: Heterogeneity in the association between parental socioeconomic indicators and childhood overweight or obesity was clearly observed across the five countries studied. Positive as well as negative associations were observed between parental socioeconomic indicators and childhood overweight, with statistically significant interactions between country and parental indicators. CONCLUSIONS: These findings have public health implications for the WHO European Region and underscore the necessity to continue documenting socioeconomic inequalities in obesity in all countries through international surveillance efforts in countries with diverse geographic, social and economic environments. This is a prerequisite for universal as well as targeted preventive actions.

Folic acid supplementation and IVF pregnancy outcome in women with unexplained infertility.

Folic acid supplements are commonly used by infertile women which leads to a positive folate status. However, the effect of folic acid supplements on pregnancy outcome in women with unexplained infertility has not been well investigated. This study evaluated folic acid supplement use and folate status in women with unexplained infertility in relation to IVF pregnancy outcome. In addition, use of folic acid supplements and folate status were compared between women with unexplained infertility and fertile, nonpregnant control women. Women with unexplained infertility used significantly more folic acid supplements and had higher median total folic acid intake from supplements compared with fertile control women (both P < 0.001). Women with unexplained infertility also had significantly higher median plasma folate and lower median plasma homocysteine concentrations than fertile women (both P < 0.001), but folic acid supplementation or folate status were not related to pregnancy outcome in women with unexplained infertility. In conclusion, folic acid supplementation or good folate status did not have a positive effect on pregnancy outcome following infertility treatment in women with unexplained infertility. Folate is one of the B vitamins which has been suggested to be related to infertility. Folic acid is an artificial form of folate which is commonly used in dietary supplements. Folic acid supplementation has been shown to increase folate concentrations and decrease concentrations of the amino acid homocysteine in the blood. Folic acid supplementation is commonly used by infertile women, but the effect on pregnancy outcome in women with a diagnosis of unexplained infertility has not been thoroughly investigated. In the present study, folic acid supplement use and folate status (concentrations of folate and homocysteine) in women with unexplained infertility were evaluated in relation to pregnancy outcome. In addition, the use of folic acid supplements and folate status were compared between women with unexplained infertility and fertile control women. Our results showed that women with unexplained infertility used considerably more folic acid supplements and had higher total folic acid intake from supplements compared with fertile control women. Women with unexplained infertility had better blood folate and homocysteine concentrations than fertile women, but folic acid supplementation or folate status were not related to pregnancy outcome following the infertility treatment. In conclusion, high folic acid intake or good folate status did not increase the possibility of a birth of a healthy baby after infertility treatment in women with unexplained infertility.

Polyamine levels in breast milk are associated with mothers' dietary intake and are higher in preterm than full-term human milk and formulas.

BACKGROUND: Polyamine intake from milk is considered essential for post-natal maturation of the immune system and small intestine. The present study aimed to determine polyamine content in human milk after preterm delivery and the association with mothers' dietary intake. In comparison, the polyamine levels were compared with those in term breast milk and some corresponding formulas. METHODS: Transitional breast milk was collected from 40 mothers delivering after 24-36 weeks of gestation, and from 12 mothers delivering after full term. Food intake was assessed in mothers delivering preterm babies using a 3-day diary. Polyamines were analysed by high-performance liquid chromatography. RESULTS: The dietary intake of polyamines was significantly associated with breast milk content but weaker for spermine than for spermidine and putrescine. Total polyamine level was higher in preterm than term milk and lower in the corresponding formulas. Putrescine, spermidine and spermine contents [mean (SEM)] in preterm milk were 165.6 (25), 615.5 (80) and 167.7 (16) nmol dL⁻¹, respectively, with the levels of putrescine and spermidine being 50% and 25% higher than in term milk. The content of spermine did not differ. CONCLUSIONS: Dietary intake of polyamines has an impact on the content in breast milk. The difference between human milk after preterm and term delivery might be considered when using donor human milk for preterm infants. The corresponding formulas had lower contents. Further studies are important for determining the relationship between tissue growth and maturation and optimal intake.

Lower polyamine levels in breast milk of obese mothers compared to mothers with normal body weight.

BACKGROUND: Obesity is associated with risks for mother and infant, and the mothers' dietary habits influence breast milk composition. Polyamines are secreted in breast milk and are essential for the regulation of intestinal and immune function in newborns and infants. The present study aimed to investigate the level of polyamines in human milk obtained from obese and normal weight mothers at different times of lactation. METHODS: Breast milk from 50 mothers was obtained at day 3, and at 1 and 2 months after delivery. The mothers had normal body weight [body mass index (BMI) < 25 kg m(-2) ] or were obese (BMI > 30 kg/m(2) ). A subgroup of obese mothers participated in a weight reduction programme during pregnancy. Polyamines were analysed using high-performance liquid chromatography. RESULTS: The total polyamine content was significantly lower at all times in breast milk from obese mothers compared to milk from controls. Spermine levels did not differ between groups at any time in contrast to the levels of putrescine and spermidine. Putrescine concentrations were highest on day 3 and spermidine and spermine were highest at 1 month of lactation. The obese mothers, who received dietary advice during pregnancy based on the Nordic Nutrition Recommendations, had higher concentrations of putrescine and spermidine in their milk than the obese mothers without any intervention. CONCLUSIONS: Polyamine concentrations were lower in breast milk from obese mothers compared to mothers with a normal weight. General dietary intervention in obese mothers increased the polyamine levels, suggesting that the low levels in obesity were at least partly associated with food habits. However, the consistency of spermine suggests a special metabolic function of this polyamine.

WHO European Childhood Obesity Surveillance Initiative 2008: weight, height and body mass index in 6-9-year-old children.

UNLABELLED: What is already known about this subject Overweight and obesity prevalence estimates among children based on International Obesity Task Force definitions are substantially lower than estimates based on World Health Organization definitions. Presence of a north-south gradient with the highest level of overweight found in southern European countries. Intercountry comparisons of overweight and obesity in primary-school children in Europe based on measured data lack a similar data collection protocol. What this study adds Unique dataset on overweight and obesity based on measured weights and heights in 6-9-year-old children from 12 European countries using a harmonized surveillance methodology. Because of the use of a consistent data collection protocol, it is possible to perform valid multiple comparisons between countries. It demonstrates wide variations in overweight and obesity prevalence estimates among primary-school children between European countries and regions. BACKGROUND: Nutritional surveillance in school-age children, using measured weight and height, is not common in the European Region of the World Health Organization (WHO). The WHO Regional Office for Europe has therefore initiated the WHO European Childhood Obesity Surveillance Initiative. OBJECTIVE: To present the anthropometric results of data collected in 2007/2008 and to investigate whether there exist differences across countries and between the sexes. METHODS: Weight and height were measured in 6-9-year-old children in 12 countries. Prevalence of overweight, obesity, stunting, thinness and underweight as well as mean Z-scores of anthropometric indices of height, weight and body mass index were calculated. RESULTS: A total of 168 832 children were included in the analyses and a school participation rate of more than 95% was obtained in 8 out of 12 countries. Stunting, underweight and thinness were rarely prevalent. However, 19.3-49.0% of boys and 18.4-42.5% of girls were overweight (including obesity and based on the 2007 WHO growth reference).The prevalence of obesity ranged from 6.0 to 26.6% among boys and from 4.6 to 17.3% among girls. Multi-country comparisons suggest the presence of a north-south gradient with the highest level of overweight found in southern European countries. CONCLUSIONS: Overweight among 6-9-year-old children is a serious public health concern and its variation across the European Region highly depends on the country. Comparable monitoring of child growth is possible across Europe and should be emphasized in national policies and implemented as part of action plans.

Multi-level influences on childhood obesity in Sweden: societal factors, parental determinants and child's lifestyle.

BACKGROUND: Swedish school children living in rural areas and in areas with low education are at excess risk of becoming overweight. This study examines influences of societal and individual characteristics (children and their parents) on prevalence of overweight and obesity, in a national sample of 7-9-year-old children. METHOD: Anthropometric and lifestyle data were collected in a nationally representative sample of 3636 Swedish children. Overweight and obesity (International Obesity Task Force (IOTF)) data were analyzed in relation to lifestyle factors, parental weight, education and breast-feeding. RESULTS: The prevalence of overweight was 15.6% including 2.6% obese. Urbanization level and parental characteristics (weight status and education) were related to risk of overweight. Overall less favorable lifestyle characteristics were observed in rural areas and for children of low/medium educated mothers. Boys had greater risk of obesity in semi-urban and rural areas but this was not true for girls. For children's overweight, the living area effect was attenuated in multivariate analysis, while there was an association with origin of parents, high parental weight and medium maternal education. For obesity, the living area effect remained in boys while having two non-Nordic parents predicted obesity in girls. Parental weight status was associated with obesity in both girls and boys. CONCLUSION: Individual and societal factors influence children's weight status, and parental weight status is a strong determinant. Including overweight and obese parents in future health promoting interventions could be a strategy to prevent children from becoming overweight, but identifying those parents may prove difficult. To ensure reaching children with the greatest needs, targeting high risk areas might be a more effective approach.

A systematic approach for the development of a kindergarten-based intervention for the prevention of obesity in preschool age children: the ToyBox-study.

The increasing childhood obesity epidemic calls for appropriate measures and effective policies to be applied early in life. Large-scale socioecological frameworks providing a holistic multifactorial and cost-effective approach necessary to support obesity prevention initiatives in this age are however currently missing. To address this missing link, ToyBox-study aims to build and evaluate a cost-effective kindergarten-based, family-involved intervention scheme to prevent obesity in early childhood, which could potentially be expanded on a pan-European scale. A multidisciplinary team of researchers from 10 countries have joined forces and will work to realize this according to a systematic stepwise approach that combines the use of the PRECEDE-PROCEED model and intervention mapping protocol. ToyBox-study will conduct systematic and narrative reviews, secondary data analyses, focus group research and societal assessment to design, implement and evaluate outcome, impact, process and cost effectiveness of the intervention. This is the first time that such a holistic approach has been used on a pan-European scale to promote healthy weight and healthy energy balance-related behaviours for the prevention of early childhood obesity. The results of ToyBox-study will be disseminated among key stakeholders including researchers, policy makers, practitioners and the general population.

Existing policies, regulation, legislation and ongoing health promotion activities related to physical activity and nutrition in pre-primary education settings: an overview.

UNLABELLED: Obesity prevention efforts for school-aged children and adolescents are increasing in number. However, little has been done to address the problem in the preschool age. To address this age group, an evidence-based preschool programme on physical activity (PA) and nutrition is developed within the ToyBox project. Environmental influencing factors such as policies and competitive health promotion activities could inhibit or induce a successful health promotion programme. This paper describes an overview of existing policies, legislation and/or regulations and health promotion activities in the preschool setting. METHOD: data were gathered on policies and activities aiming to improve healthy eating and PA of young children (age group 4-6 years) in Belgium-Flanders, Bulgaria, Germany, Greece, Poland and Spain. A limited number of influencing policies, regulations and/or legislation exists; agenda setting of health promotion and policy evaluations in all relevant policy areas was lacking. Also, health promotion activities in preschool the setting did not exist in all six European countries and high-quality preschool-based health interventions existed in three of the six ToyBox countries.

Overweight and obesity in a representative sample of schoolchildren - exploring the urban-rural gradient in Sweden.

To present the prevalence and urban-rural differences of overweight and obesity in 7-9-year-old Swedish schoolchildren, we used anthropometric data from a nationally representative survey performed in 2008. Trained staff weighed and measured 4538 children in grades 1 and 2 in 94 primary schools. Weight classification was performed using the IOTF reference and school areas were classified based on level of urbanization and area-level education. Overweight was found in 17% of the children including 3% obese. For overweight, odds-ratios were 1.33 and 1.61 (significant) in semi-urban and rural areas, relative to urban areas. After adjusting for area-level education, differences by degree of urbanisation were greatly attenuated and non-significant. For obesity urban-rural differences were observed in boys only and remained after adjustment for area-level education. For area-level education, risk estimates were significantly elevated and unaffected by urbanization and gender, odds-ratios 1.75 and 2.21 for overweight and 2.62 and 3.69 for obesity, in medium- and low-education areas compared to high-education areas. This supports earlier reports identifying areas with low socioeconomic status as high-risk areas for overweight and obesity. However, this study also suggests that gender should be considered when targeting children in urban as well as rural communities for health promoting interventions.

Personal, social and environmental predictors of daily fruit and vegetable intake in 11-year-old children in nine European countries.

OBJECTIVE: To investigate potential personal, social and physical environmental predictors of daily fruit intake and daily vegetable intake in 11-year-old boys and girls in nine European countries. SUBJECTS: The total sample size was 13 305 (90.4% participation rate). RESULTS: Overall, 43.2% of the children reported to eat fruit every day, 46.1% reported to eat vegetables every day. Daily fruit intake and daily vegetable intake was mainly associated with knowledge of the national recommendations, positive self-efficacy, positive liking and preference, parental modeling and demand and bringing fruit to school (odds ratio between 1.40 and 2.42, P<0.02). These factors were associated fairly consistently with daily fruit intake across all nine European countries, implying that a rather uniform intervention strategy to promote fruit can be used across Europe. For vegetables, the pattern was, however, less consistent. Differences between countries in cooking and preparing vegetables might be responsible for this larger diversity. CONCLUSIONS: This study showed that especially a combination of personal and social factors is related to daily fruit and vegetable intake in schoolchildren. This shows that a comprehensive multilevel intervention strategy based upon a series of individual and social correlates will be most promising in the promotion of daily fruit and vegetable intake in children.

Serum lipids, glucose and insulin levels in healthy schoolchildren aged 9 and 15 years from Central Sweden: reference values in relation to biological, social and lifestyle factors.

BACKGROUND: There is a shortage of reference values for cardiovascular risk factors such as serum lipids, glucose and insulin related to biological, social and lifestyle factors for Swedish children and adolescents. Such values are needed for planning and evaluation of public health activities, and for clinical use. DESIGN AND METHODS: Data for this cross-sectional, school-based study were collected during a school year (September to May). A random sample of 1137 girls and boys aged 9 and 15 years from two locations in central Sweden participated in the study, and blood samples were taken from 969 of them. METHODS: Fasting serum blood samples were analysed for triglycerides, total cholesterol, high-density lipoprotein cholesterol, glucose and insulin. Physical examination included measurement of height, weight and pubertal status. Questionnaires provided family background data. Total physical activity was measured by accelerometer registration. RESULTS: Serum levels differed significantly between age and gender groups and were correlated to pubertal status. Neither genetic nor socio-economic background nor smoking status influenced the serum levels. Insulin levels were elevated in subjects with a body mass index in the highest decentile, compared with the levels in the rest of the subjects. The insulin levels were inversely associated with total physical activity, and physical activity varied with season. CONCLUSIONS: Pubertal status (biological age) should to be considered in the interpretation of serum values in schoolchildren rather than chronological age. The interpretation of insulin values should include both body mass index and physical activity level, and perhaps also season. Previously described regional differences in serum lipid levels in Swedish adults seem to be present also in children.

Large social disparities in spontaneous preterm birth rates in transitional Russia.

OBJECTIVE: This study estimated the effect of maternal sociodemographic, obstetric and lifestyle factors on the risk of spontaneous preterm birth in a Russian town. METHODS: All women with singleton pregnancies registered at prenatal care centres in Severodvinsk in 1999 comprised the cohort for this study (n=1559). Analysis was based on spontaneous live singleton births at the maternity home (n=1103). Multivariable logistic regression was applied to quantify the effect of the studied factors on the risk of preterm birth. Differences in gestation duration were studied using multiple linear regression. RESULTS: In total, 5.6% of all spontaneous births were preterm. Increased risks of preterm delivery were found in women with lower levels of education and in students. Placental complications, stress and a history of fetal death in previous pregnancies were also associated with elevated risks for preterm delivery. Smoking, hypertension and multigravidity were associated with reduced length of pregnancy in metric form. CONCLUSION: In addition to medical risk factors, social factors are important determinants of preterm birth in transitional Russia. Large disparities in preterm birth rates may reflect the level of inequalities in transitional Russia. Social variations in pregnancy outcomes should be monitored.

Comparative analysis of nutrition data from national, household, and individual levels: results from a WHO-CINDI collaborative project in Canada, Finland, Poland, and Spain.

STUDY OBJECTIVE: This project determined to what extent data on diet and nutrition, which were collected in a non-uniform manner, could be harmonised and pooled for international and national comparison. DESIGN: Direct comparisons of dietary data between studies were made using food balance sheets (FBS), household budget surveys (HBS), and individual dietary data (IDS); comparisons were also made within countries. Differences in study design and methodological approaches were taken into consideration. Data from research projects from the following four World Health Organisation (WHO) Countrywide Integrated Noncommunicable Disease Intervention (CINDI) countries were included-Canada, Finland, Poland, and Spain. MAIN RESULTS: FBS overestimated food consumption and nutrient intake compared to IDS. Results between HBS and IDS were quite similar, except for fish, meat, pulses and vegetables, which were underestimated by HBS, and sugar and honey and cereals, which were overestimated. Percentages of energy from fat, carbohydrates and proteins were higher when estimated from FBS, HBS, and IDS respectively. CONCLUSIONS: Results suggest that estimations from these three sources of dietary data are difficult to compare because they are measuring different levels of dietary information. The understanding of their relations may be important in formulating and evaluating a nutrition policy.

Breastfeeding in countries of the European Union and EFTA: current and proposed recommendations, rationale, prevalence, duration and trends.

UNLABELLED: Recommendations suggest exclusive breast feeding for at least the first 4 to 6 months after birth. Paradoxically, an overwhelming proportion of breast feeding (BF) data in Europe refers to all BF, i.e. not only exclusive but also partial BF (including formula, juices, water, sweetened water etc). This makes it difficult to estimate to what extent the recommendations are met. There is currently strong evidence for recommending exclusive breast feeding for at least 6 months. Exclusive BF has progressively gained scientific support. Prevention of infections, allergies and chronic diseases and a favourable cognitive development are highlighted in the recent scientific literature. Further long-term studies on the effects of BF on prevention of chronic disease in the adult are needed. Great differences exist in BF prevalence and duration both within and between European countries. Trends point towards higher prevalence and duration, with some exceptions. Young mothers breast feed less than older mothers; single and/or less educated mothers breast feed less than married mothers with more education. However, inefficient and unreliable monitoring systems prevail, and the data are scarce, not only on exclusive BF but also on demographic, socio-economic, psychosocial and medical determinants of BF patterns. National BF coordinators have not been appointed in many countries, and only every second country has promotion of BF incorporated into their national plan of action for nutrition. CONCLUSIONS: Efficient surveillance systems, comparable across Europe and using common definitions and methodology, need to be developed. These should include determinants of breast feeding. A European consensus conference should urgently be organised, in which strategies for successful promotion of exclusive BF should be particularly considered. There is now strong evidence for a recommendation to breast feed exclusively for about 6 months, which is more than the duration recommended previously.

The school setting: an opportunity for the implementation of dietary guidelines.

Nutrition, physical activity and health related promotion programmes in schools have developed into a mature field of research over the past decades. A number of success factors have been identified and evidence-based interventions have been performed. However, the school setting as an arena for evidence-based health promotion programmes, is still not used to its full potential. Schools provide an excellent arena for reaching large segments of the population, such as young people, school staff, families and the surrounding community. There is a need for an overview regarding the current status of nutrition, physical activity, related health as well as support structures in the EU member states. Based upon such an analysis, a consensus report should be written, pointing out the major problems at hand. Self-assessment tools for national as well as for school level should be produced, in order to guide changes, but also to include an element of continuous assessment of change, for evaluation purposes.

Breastfeeding determinants and a suggested framework for action in Europe.

This is a background paper for the EURODIET initiative. A number of international initiatives and documents were identified, such as the Baby-Friendly Hospital Initiative, the International Code of Marketing of Breast Milk Substitutes and a number of consensus reports from professional groups, that propose ways forward for breastfeeding promotion. These point at a range of initiatives on different levels. The determinants for successful breastfeeding have to be identified. They can be categorised into five groups; socio-demographic, psycho-social, health care related, community- and policy attributes. A framework for future breastfeeding promoting efforts on European level is suggested, within which these determinants are considered. A common surveillance system needs to be built in Europe, where determinants of breastfeeding are included. There is also a need for a surveillance system which makes it possible to use the collected data on local level, not only on national and supranational level. Combined with a thorough review of the effectiveness of already existing breastfeeding promotion programmes, a co-ordinated EU-EFTA action plan on breastfeeding should be formulated and implemented within a few years. Urgent action could take place in parallel, especially targeting young, low-income, less educated mothers.

Physical activity in relation to aerobic fitness and body fat in 14- to 15-year-old boys and girls.

The purpose of this study was to examine the strength of the relationship between different variables of physical activity and aerobic fitness and body fat in adolescent boys and girls. Activity energy expenditure (AEE), time spent in a sedentary state, and time spent engaged in moderate and vigorous physical activity (MVPA, > or = 50% peak oxygen uptake, VO2peak) were assessed by the minute-by-minute heart rate monitoring method in 82 randomly selected 14- to 15-year olds (42 boys, 40 girls). Body fat was determined by measuring skinfold thicknesses. VO2peak was measured by indirect calorimetry. Somatic maturity level was determined by percentages of adult (i.e. 18 years) height attained at examination. AEE was related to aerobic fitness for both genders (boys, r = 0.30, P = 0.056; girls, r = 0.45, P = 0.003). For boys, there was a significant relationship between maturity level and VO2peak (r = 0.48, P < 0.001). For both genders, body fat was significantly and negatively related to VO2peak (r = -0.48 and r = -0.43, P < 0.01). Body fat and maturity explained 47% of the variation in VO2peak in boys, whereas AEE and body fat explained 22% of the variation in VO2peak in girls. No significant associations between physical activity variables and the data on body fat were observed. The total amount of physical activity (AEE) was related to VO2peak, at least in adolescent girls. Although VO2peak seems to be influenced by the maturity level in adolescent boys, the data support the promotion of a daily active lifestyle among young people.

Heart rate as an indicator of the intensity of physical activity in human adolescents.

The aims of this study were, in a group of adolescents, firstly to identify the absolute heart rates (HR) and the percentages of maximal heart rates (HRmax) corresponding to 40%, 60% and 80% of peak oxygen uptake (PVO2), secondly to identify absolute and relative (%PVO2) oxygen uptakes (VO2) corresponding to HR of 120, 140 and 160 beats.min-1, and thirdly to examine a possible effect of fatness and fitness on the relationship between HR and VO2. The subjects were 127 (60 boys, 67 girls) adolescents with a mean age of 14.8 (SD 0.3) years. The HR and VO2 were measured by means of an incremental exercise test to exhaustion. Linear regressions were performed for the HR-VO2 and VO2-HR relationships using absolute and relative (%HRmax, %PVO2) data for each individual. From these regressions, target HR and VO2 were computed. Average target HR corresponding to 40%, 60% and 80% of PVO2 were: 119 (SD 9), 145 (SD 9), 171 (SD 8), and 120 (SD 10), 146 (SD 8), 172 (SD 8) beats.min-1 for boys and girls, respectively. Average VO2 corresponding to HR of 120, 140 and 160 beats.min-1 were: 22 (SD 5), 30 (SD 5), 38 (SD 6) and 18 (SD 4), 24 (SD 4), 31 (SD 4) mlO2.kg-1.min-1 for boys and girls, respectively. An analysis of covariance showed a significant fitness effect (P < 0.001) for predicted VO2 at all HR studied. The results suggest that the use of absolute HR to define exercise intensity levels when assessing young people's physical activity using HR monitoring detracts from the validity of the interpretation of the data.

Physical activity assessed by activity monitor and doubly labeled water in children.

PURPOSE: To validate the Computer Science and Application's (CSA) activity monitor for assessment of the total amount of physical activity during two school-weeks in 9-yr-old children and to develop equations to predict total energy expenditure (TEE) and activity energy expenditure (AEE) from activity counts and anthropometric variables. METHODS: A total of 26 children (15 boys and 11 girls, mean age 9.1 +/- 0.3 yr) were monitored for 14 consecutive days. TEE was simultaneously measured by the doubly labeled water method. Averaged activity counts (counts.min(-1)) were compared with data on: 1) TEE, 2) AEE = TEE minus basal metabolic rate (BMR; estimated from predictive equations), and 3) daily physical activity level (PAL = TEE/BMR). RESULTS: Physical activity determined by activity counts was significantly related to the data on energy expenditures: TEE (r = 0.39; P < 0.05), AEE (r = 0.54; P < 0.01), and PAL (r = 0.58; P < 0.01). Multiple stepwise regression analysis showed that TEE was significantly influenced by gender, body composition (body weight or fat free mass), and activity counts (R(2) = 0.54--0.60). AEE was significantly influenced by activity counts and gender (R(2) = 0.45). There were no significant differences between activity counts and PAL in discriminating among activity levels with "low" (PAL < 1.56), "moderate" (1.57 < or = PAL > or = 1.81), and "high" (PAL > 1.81) intensity. CONCLUSION: Activity counts from the CSA activity monitor seems to be a useful measure of the total amount of physical activity in 9-yr-old children. Activity counts contributed significantly to the explained variation in TEE and was the best predictor of AEE.